Circuit breaker



April 4, P ER ETAL CIRCUIT BREAKER Filed March 19. 1942 5 Sheets-Sheet 3131 fig. 9. 140

l l ORS Benjamin Pflaker and Herbert L. Raw/272s Patented Apr. 4, 1944CIRCUIT BREAKER Benjamin 1. Baker, Turtle Creek, and Herbert L.

Rawlins, Pittsburgh, Pa,

assignors to Westinghouse Electric & Manufacturing Company,

a corporation of Penn- East Pittsburgh, Pa.,

sylvania Application March 19, 1942, Serial No. 435,381

29 Claims.

This invention relates to improvements in circult breakers, and, moreparticularly, to circuit breakers of the type wherein arc extinction isat least in part efiected by subjecting the are drawn to a blast of arcextinguishing fluid, either liquid or gaseous. More specifically, thepresent invention concerns improvements in circuit breakers of theaforesaid type which have a pressure chamber in which the arc is drawn,said pressure chamber containing a liquid or gaseous are ex-.tinguishing fluid, means for increasing the pressure of the liquid orgaseous arc extinguishing fluid contained in said pressure chamber to apredetermined pressure, at which time the pressure of the fluid in saidpressure chamber is suddenly released to effect extinguishment of thearc and a consequent interruption of the circuit through the breaker.

Our invention is not limited in all of its applications. to theutilization of a gaseous arc extinguishing fluid. A liquid fluid maywell be used, but for the purpose of illustrating a preferred form ofthe invention a gaseous fluid is employed in the followingspecification.

When the present invention is applied to circuit breakers of the typewhich effect extinguishment of the are by a blast of a gaseous areextinguishing fluid, it is possible to have the pressure generatingmeans disposed within the pressure chamber also augment the existingsupply of gaseous arc extinguishing fluid contained Within the pressurechamber. In other words it is possible to have material disposed withinthe pressure chamber, which, when subjected to an arc, will evolveadditional gaseous arc extinguishing fluid. In this event the supply ofgaseous arc extinguishin' fluid contained within the pressure chamberwill not only be increased. but also the pressure will be raised withinthe soressure chamber.

When the invention is applied to a liquid type circuit breaker, it isnot necessary to furnish a gas evolving solid material within thepressure chamber. The are acting upon the liquid disposed within thepressure chamber would furnish the required pressure. For purposes ofillustration, however, the invention will be described when it isapplied to a breaker which utilizes a gaseous are extinguishing fluid toeiiect the em tinction of the arc.

We have found that the conventional compressed air circuit breaker,which utilizes a nozzle through which the compressed air passes toextinguish the are drawn in the nozzle, seems to require air pressureswhich increase rapidly with increased k. v. a. interrupting capacity.The

highest rating now on the market for this type of compressed air circuitinterrupter does not exceed 800,000 k. v. a. for power house type ofinterrupters, and it requires pressures up to 240 pounds per squareinch. It is apparent that in order to extend the range of this type ofinterrupter to 1,000,000 or 1,500,000 k. v. a. interrupting capacity,impractical pressures would be required.

We have observed from the results obtained on a self-generated gas blasttype of breaker, which successfully interrupted 48,000 amperes at 7,600volts and which consisted of a structure which contained a gasgenerating break and an arc interrupting break, that in order to makethe gas evolving structure adequate to interrupt the low currents, thepressure generated during the interruption of high currents was of theorder of 1,000 pounds per square inch. Pressures of this order are notonly unnecessary, but are dangerous to life and property.

In the following application of our invention, we describe a structurewhich permits the use of gas at nominal pressures (less than 200 poundsper square inch) for producing mechanical operation of the contacts andinterrupting the low and medium values of current. For the interruptionof the higher values of current which require still more pressure, wehave provided a device incorporated within the interrupter, whichgenerates an augmenting gas supply. Consequently, if low currents arebeing interrupted, the generated gas will be negligible in comparisonwith the gas supply furnished by the reservoir used to actuate thebreaker. On the other hand, if the current which is being interrupted isof a comparatively high value, the compressed gas will serve to operatethe breaker mechanically and then will be cut off by a check valve whichcloses when the pressure produced by the self generating device withinthe breaker exceeds the pressure provided by the external gas source.

One embodiment of our invention also concerns the provision of aself-generating gas type of breaker, which generates gas at one pointwithin the breaker, which gas produces a rise 03': pressure within thebreaker to operate a vent disposed at another point in the housing ofthe breaker.

The main object of the present invention is to provide a circuit breakerof the aforesaid type, which by virtue of the location of the structuralparts thereof will render improved and more effective performance.

A further object of the present invention is to PrQ ide a circuitbreaker which comprises a pressure chamber, a liquid or a gaseous areextinguishing fluid disposed within said pressure chamber, meansinitiated by an are drawn within said pressure chamber to raise thepressure of the fluid within said pressure chamber, means responsive tothe pressure within said pressure chamber for actuating a vent disposedwithin a wall of said pressure chamber, said vent causing a blast of arcextinguishing fluid to effect extinguishment of an are drawn within saidpressure chamber.

A more specific object of the-present invention is the provision of animproved circuit breaker which has a pressure chamber in which either aliquid or gaseous arc extinguishing fluid is disposed, means external tosaid pressure chamber for supplying the required amount of areextinguishing fluid at the proper pressure to effect extinguishment ofthe low and medium values of current, and means disposed within saidpressure chamber for utilizing a series are on the high values ofcurrent to increase the pressure within said pressure chamber to theamountnecessary to effect the extinguishment of the higher values ofcurrent. I

A more specific object of the present invention is the provision of animproved circuit breaker of the aforesaid type which utilizes anexternal supply of arc extinguishing fluid for low current interruption,but yet on high current interruption utilizes also are extinguishingfluid generated within the breaker itself, thus resulting in economicalbreaker performance.

Another object of the present invention is the provision of an improvedcircuit breaker of the aforesaid type which generates arc extinguishingfluid at one point within the breaker, stores said generated arcextinguishing fluid within a storage chamber until the pressure there issufficient to interrupt the current passing through the breaker, andthen by the actuation of suitable vent means renders said stored areextinguishing fluid available to efiect the interruption of the currentat a different point within the breaker.

Another object of the present invention is the provision of an improvedcircuit breaker of the aforesaid type which generates arc extinguishingfluid within a generating means, stores said generated arc extinguishingfluid until the pressure thereof is suflicient to eflect theinterruption of the breaker current, and then by the actuation ofsuitable vent means utilizes said generated fluid to effect circuitinterruption at a point in the interior of said generating means.

Another object of the present invention is the provision of an improvedcircuit breaker which employs either a supply of arc extinguishing fluidfurnished exclusively by an external source, or the combination of anexternal and an internal source of arc extinguishing fluid, said areextinguishing fluid serving a dual purpose of assisting arc removal andalso arc interruption.

Another object of the present invention is the provision of an improvedcircuit breaker which utilizes a plurality of serially related arcs, oneor more of said arcs assisting in the production of arc extinguishingfluid under pressure to effect the interruption of one or more other ofsaid plurality of serially related arcs.

A more specific object of the present invention is the provision of animproved circuit breaker of the aforesaid type which on low currentinterruption utilizes an external source of arc extinguishing fluid forare removal and for are interruption, and on high current interruptioncuts off said external source and utilizes exclusively an internalsource of arc extinguishing fluid, thus eliminating the necessity of ahigh pressure external source for high current interruption.

A specific object is the provision of a circuit breaker which may beused in conjunction with a relatively low pressure external source ofarc extinguishing fluid, such as air, for the mechanical actuation ofthe circuit breaker mechanism and for the extinction of low currentarcs, but which provides its own supply of high pressure areextinguishing fluid for high current interruption.

It is to be clearly understood that in the following description of ourinvention as applied specifically to circuit breakers of the type whichutilize a gaseous arc extinguishing fluid, we do not intend to limit thescope of our invention entirely to gaseous type circuit breakers whichare preferred for some applications. Instead of the arc reacting on agas evolving solid material as in the preferred gaseous type breaker, itcould react on a liquid arc extinguishing fluid disposed within thepressure chamber to generate the requisite pressure necessary for areinterruption.

Other objects and advantages will appear more fully in the followingdescription when read in connection with the accompanying drawings, in

which:

Figure 1 is a side elevational view, partly in section, of a circuitbreaker constructed in accordance with the principles of our invention,and shown in the partly open-circuit position;

Fig. 2 is an enlarged transverse sectional view of the circuit breakershown in Fig. 1, taken along the line ll-II in Fig. 1 and looking in thedirection of the arrows;

Fig. 3 is an enlarged view of one of the gas generating insulatingplates used in the gas generator chamber of Fig; 1 looking in thedirection of the arrows on the line III-III of Fig. 1;

Fig. 4 is a side elevational view, partly in section, of a modified typeof circuit breaker incorporating the principles of our invention, thecircuit breaker being shown in the partly open-circuit position;

Fig. 5 is an enlarged view of the elements making up the gas generatingchamber of Fig. 4, looking in the direction of the arrows on the lineV-V of Fig. 4; 1

Fig. 6 is an elevational view, partly in section, V

of a modified type of circuit breaker also embodying our invention, andshown in the partly open-circuit position;

Fig-7 is a fragmentary transverse sectional view of the circuit breakershown in Fig. 6, taken substantially on the lineVIL-VII of Fig. 6 andlooking in the direction of the arrows;

Fig. 8 is an enlarged view of one of the gas generating insulatingplates used in the gas generating chamber Of Fig. 6, looking in thedirection of the arrows on the line VIII-VIII of Fig. 6; and

Fig. 9 is a side elevational view, partly in section, of anotherembodiment of our invention, the breaker being shown in the partly opencircuit position.

Referring to Figure l, the reference numeral 0 designates a suitablebase plate, preferably of metal, supported upon metal legs 3. The baseplate i supports a tubular insulator 5 which is secured to an annularflanged support plate I which has a centrally disposed aperture 9 there-Threadedly inserted in the centrally disposed aperture 9 is aninsulating conduit ll passing through the tubular insulator and leadingto an lectrically actuated valve mechanism generally designated by thereference numeral IS. The valve mechanism l3 controls the passage offluid through the conduit II from a storage tank l5, where the fluid ismaintained under pressure by suitable means not shown.

The conduit ll leads through the centrally disposed aperture 9 into aclosed (except for vents which will be described hereinafter)longitudinal chamber generally indicated by the reference numeral IT.The longitudinal chamber l'l comprises a longitudinal tubular casing l9of insulating material, the lower end 01' which is threadedly secured tothe annular flanged support plate I, and the upper end of which isclosed by a flanged annular metallic closure member 2 I. The flangedannular closure member 2| has acentrally disposed vent 23 therein, whichis normally closed by a valve mechanism generally designated by thereference numeral 25, which will be described hereinafter.

A fluid directing baille 21 is disposed within the closed chamber IT, atthe lower end thereof, and this baiile has a centrally disposed aperture29 therein which serves to direct the fluid coming upwardly through theconduit H from the storage tank |5 between a stationary contact 3| and amovable contact 33 when the valve mechanism I3 is actuated. A checkvalve 35 disposed between the directing ballle 21 and the annularsupport plate 1 opens when the pressure of fluid in conduit H is greaterthan the pressure of fluid within the closed chamber l7, and closes whenthe pressure of fluid within the chamber l! is greater than the pressureof fluid within conduit II.

The movable contact 33 is actuated to open and closed circuit positionsby a crank arm 3'1 pivoted at 39 to the framework of a piston chamber4|. A piston 43 adapted for reciprocating longitudinal motion within thepiston chamber 4| is connected to the crank arm 37, so that whencompressed fluid from the storage tank i5 is admitted by an electricallyoperated valve 35 through a conduit 47 to the piston chamber ii, theresulting upward motion of piston 43 will close the movable contact 33.A compression spring 19 disposed between the upper end of the pistonchamber 6i and the piston 43 serves to bias the piston 83 downward andhenc to bias "the movable contact 33 to the open circuit positron.

A latch mechanism generally indicated by the reference numeral 5i servesto latch the crank ill in the closed-circuit position, thus pershittingthe breaker to be closed and to remain closed by a momentary fluid pulsethrough the electrically operated valve 85. The latch mechanism may beactuated by a solenoid 53 schematically indicated in Fi 1.

From the description of the breaker thus far,

it is obvious that momentary actuation of the valve mechanism 65 resultsin closing the breaker, the latch mechanism 5| serving to maintain thebreaker in the closed-circuit position. When it is desired to open thebreaker, solenoid E3 is electrically actuated thus permitting the biasexerted by the compression spring 49 to open the breaker. The valvemechanism d5 releases the pressure within the piston chamber 4| topermit piston 83 to be moved downward by the compression spring d9.

When the breaker is closed, the electrical circuit consists of aterminal cable 55, terminal stud bolt 51, flexible cable 59, movablecontact 33, stationary contact 3|, terminal stud SI, and terminal cable63.

Electrically connected to the terminal stud bolt 51 and disposed withinthe longitudinal tubular insulating casing l9 adjacent the inner wallthereof and spaced slightly above the movable contact 33 is a metallicarcing horn 85. Diametrically opposite to the arcing horn 65 is ametallic arcing horn 61 spaced by an insulating barrier 69 from thestationary contact 3|, and extending upward adjacent the inner wall ofcasing I9 to a point in the immediate vicinity of vent 23. Here themetallic arcing horn 61 is electrically connected by a flexibleconductor H to an electrode 13 which is biased by acompression spring 15to close the vent 23. The electrode I3 is guided in its longitudinalmotion by a spider 71 disposed in the upper end of a piston chamber 19,which vents at its other end through a conduit 8| to the atmosphereoutside the casing l9. A piston 83 secured to the lower end of theelectrode 13 is responsive to the fluid pressure within the casing I9and is adapted to move downward within the piston chamber 19 against thebiasing action of compression spring 75 when high fluid pressure existsin the casing Hi. The vent at the back side of the piston 83 throughconduit 81 to the outside atmosphere eliminates any back pressure actingupon piston 83.

Disposed within the casing l9 and extending longitudinally thereof are aplurality of relatively thin insulating plate members 85 formed of anysuitable material which emits a vapor or gas when exposed to the actionof an arc, such as horn fiber, boric acid, etc. The plate members 85 arespaced from each other and are supported by two insulating supportmembers 81 secured by screws 89 to the inner wall of casing l9, as moreclearly shown in Fig. 2. Each plate 85 has a wedgeshaped slot 9!therein, as more clearly shown by Fig. 3, the slots aligning when theplates 85 are assembled on the two insulating supports 81 to form aninverted V-shaped arc passage 93, as more clearly indicated in Fig. l.

A metallic rod extending exteriorly of the casing is serves toelectrically connect the metallic closure member ill to the terminalstud iii, the reason for which will appear hereinafter.

The operation of the circuit breaker shown illustrated in Figs. 1, 2 and3 will now be described together with the method utilized to efiect arcextinction. When the breaker is in the closedcircuit position movablecontact abuts with stationary contact "the latch mechanism 5imaintaining the two contacts 33 and iii in abutting relation. Thepressure within the casing is is normal, and hence electrode 23 withinthe upper portion of the casing 69 is biased by the cornpression spring35 to close the vent 23 in the metallic closure member 2 6. Valvemechanism 33 not being operated, check valve 35 rests upon the flangedsupport plate member 7!, and the electrical circuit through the breakeris as has been previously described, that is terminal cable 55, studbolt 57, flexible cable 59, movabl contact 33, stationary contact 33.stud bolt El, and terminal cable 63.

W hen it is desired to open the electrical circuit through the breaker,or when overload conditions exist in the external electrical circuit,solenoid 53 is electrically actuated to release crank arm 37] and topermit compression spring 49 to move crank arm 537i downward, and henceto move movable contact 33 to the left.' At the same time that solenoid53 is electrically actuated, valve mechanism I3 is also actuated toeflect the admittance of fluid from the storage tank I5 through thevalve mechanism I3, through conduit II to the casing I9, which is nowclosed at its upper end. When movable contact 33 separates fromstationary contact 3| an arc will be drawn between the two contacts 33and 3|. The upward rushing fluid from the storage tank I5 will move thisdrawn are up past the insulating barrier 59 to the two metallic arcinghorns 65 and 61 to the position 90; as shown in Fig. l. The electricalcircuit through the breaker now consists of the following: terminalcable 55, stud bolt 57, metallic arcing horn 65, the are 90 itself,metallic arcing horn 67, flexible conductor II, electrode I3 (now.

closed against vent 23) metallic closure member ZI, conducting rod 35,stud bolt GI, and terminal cable 53.

The upwardly rushing fluid from the storage tank I5 through conduit IIand the check valve 35 builds up the fluid pressure within the casingI9, so that piston 83 responsive to this pressure 7 opens the electrodeI3 to draw a second are between the electrode I3 and the vent or nozzle23. The electrical circuit now through the breaker is the same as thatimmediately described above with the exception that there are two arcsin series, one between the arc horns I55 and $7, and a second betweenelectrode 13 and nozzle 23.

The fluid from the storage tank I5 now passes from the lower end of thecasing I9 up against the arc drawn between the arcing horns 65 and El,up between the insulating plates 85, and finally out of the casing I9through the nozzle 23. This passage of fluid from the tank It entirelythrough the longitudinal casing I9 'and out through the nozzle 23 servesto move the arc farther up the arcing horns t5 and 6? to force the arcto intimately engage the insulating plates 85, and hence to evolve vaporor gas from the platestie as a result of the direct action of the arc.thereon.

Assuming that the current through the breaker to be interrupted is high,the amount of gas or vapor evolved from the plates 85 as a result of theare playing thereon will correspondingly be high, and will cause thepressure within the casing I9 to rise sufiiciently to close the checkvalve 35. This large amount of evolved gas from the plates 85 as aresult of high current through the breaker will pass up through theplates 05, the upper portions of which serve to cool the evolved gas andto delonize the same. In absorbing the heat from the evolved gas theupper portions of the plates 85 give on additional gas or vapor which isat a lower temperature than the gas evolved from the lower portions ofthe plates 85. Thus during high current interruption gas is generated inthe plates 85 first from the direct action of the are on the lowerportion of the plates 85, and secondly as a result of absorption by theupper portions of the plates 85 of the heat contained in the firstevolved gas. Thus the currentthrough the interrupter is extinguished atthe nozzle 23 of the interrupter.

It will be apparent that we have provided an interrupter which serves tointerrupt low and medium values of current by the blast of arcextinguishing gas produced in the storage tank I5, the compressed gasstored in storage tank I5 also serving to operate the contacts of theinterrupter; For the interruption of high values of current, thepressure of the gas generated by the are on the plates 35 will besumcient to close the check valve 35 and to extinguish the are drawnbetween the electrode I3 and the nozzle 23. It

. will, therefore, be apparent that the design of the gas generatinginsulating plates 85 will be facilitated inasmuch as they can bedesigned to extinguish only the high values of current through thebreaker. Consequently, there is a reduction in the deterioration of thegas evolving insulating plates 85 as compared to breakers of the priorart wherein the gas evolving plates had to be designed for theinterruption of low and also high values of current. Our constructionalso results in a minimum of external dimensions for the breaker, andfor quicker extinguishing action for the lower and medium currents as aresult of the utilization of an external source of compressed gas. Itwill furthermore be apparent that the external source of compressed gasmay be used for the actuation of the contact operating mechanism.

' By the provision of gas evolving insulating plates 85, we haveprovided a safety feature in case of a loss of pressure of the gasstored in storage tank I5. In other words, should the pressure decreasein the storage tank I5 at least the high values of currents will beextinguished as a result of the evolving of gas from the insulatingplates 85.

By utilizing an external source of compressed gas and by the provisionof an internal source of gas, we have obtained very uniform arcing timeover the entire current range of the breaker. Thus the high values ofcurrent are extinguished quickly as a result of the large amount of gasevolved in the plates 85, and the lower values of current are alsoextinguished quickly by the use of the compressed gas stored in thestorage tank I5. Compression spring .15 is so designed as not to permitelectrode it to move away from nozzle 23 unless the pressure of gaswithin casing I9 is sufficient to interrupt the are drawn betweenelectrode l3 and nozzle 23.

In the embodiment of our invention illustrated in Fig. 4, there is showna cylindrical insulating casing 97, the ends of which are closed byinsulating closure members 99 and Illl which are threadedly secured tothe insulating casing 9?. A movable contact I03, actuated by mechanismnot shown, engages stationary contact I05 in the closed circuit positionof the breaker.

When the breaker is in the closed circuit positlon, the electricalcircuit therethrough consists of the terminal cable IIlI, terminal studbolt I09, flexible cable I I I, movable contact I03, stationary contactI05, terminal stud H3, and terminal cable H5.

Directly above the movable contact I03 is provided an arcing horn I IIextending longitudinally upward within the insulating case 9'I. Abovethe stationary contact I05 is an insulating barrier I00, on the upperside of which is disposed a second arcing horn H9. The arcing horn M9extends longitudinally upward within the casing 97, and at its upper endis electrically secured to a flexible cable I 2I, the other end of whichis secured to a movable electrode I23. The movable electrode I23 isguided by a bracket I25 for reciprocatin longitudinal movement within apiston chamber I29, a piston I27 being secured to the left-hand end ofthe electrode I23. The piston chamber I 29 is internally provided withstops I39 which terminate the motion of the piston I21 at the end of itsleftward motion, the rightward motion of the piston I2? being determinedby the electrode I 23 engaging a metallic nozzle I M which is screwthreaded into the side wall or the casing 91.

The piston chamber I29 is secured by the stud I3I to the wall of theinsulating casing 91 and a vent I40 is provided to relieveany'back-pressure on the rear side of the piston I21. Pins I32 securedto the inner wall of the piston chamber I29 support pivotal spring guiderods I31 around which are encircled compression springs I35. The pivotedspring guide rods I31 are provided with slots I35 therein to engage pinsI33 secured to the piston I21. Consequently, the piston I21 is biased bythe compression springs I35 to cause the electrode I23 to engage and toclose the nozzle MI.

It will be noted that by the arrangement of the pivoted spring guiderods I31 with the compression springs I35 engaging the pins I33 securedto the piston I21, the force required to maintain the piston I21 at theend of its left hand position will be less than that required toinitially move the piston I21 toward the left.

A conductor I43 is secured to the nozzle MI at one end and the other endof the conductor I43 is secured to the terminal stud I I3.

Supported on two insulating support members I 45, only one of which isshown, and disposed within the casing 91 are a plurality of plates.These plates comprise plates M composed of magnetic materialinterspersed with gas evolving insulating plates I41. Fig. 5 shows theconfiguration of the plates I41 and 5 35, it being noted that both ofthese plates are provided with a wedge-shaped slot I49. When the platesMl and M5 are assembled in stacked relation on the insulating supportmembers it, the slots It?) align so as to form an arc chamber I55disposed directly above the stationary and moving contacts Hi5 and I53.

The operation of the interrupter will now be explained. When it isdesired to open the break er or when an external overload exists in thecircuit connected through the interrupter, suitable contact operatingmechanism, not shown,- is actuated to move the movable contact i S tothe left, thus drawing an are between the movable contact I03 and thestationary contact M35. The magnetic field formed about the arc is distorted by the plates I435 composed of magnetic material so that the aredrawn between the movable contact I03 and the stationary contact its isforced in an upward direction to be positioned within the arc chamberI5I. There the are reacts on the gas evolving plates Hill, which may becomposed of horn fiber, boric acid or any other suitable gas evolvingmaterial, to generate an arc extinguishing gas which causes the presisure to rise within the insulating casing 9i". As the arc reacts on theplates Ml to generate more are extinguishing gas, the pressure rises toa sufficient value to cause the piston I2l to overcome the biasingaction of the compression springs I35 and move to the left, thus drawinga second series are between the electrode 23 and the metallic nozzle Mi.

The electrical circuit through the interrupter now consists of theterminal cable ifl'l, terminal stud bolt I09, arcing horn ill, the arethrough the arcing chamber I5I, the arcing horn II9, the flexible cableI2I, electrode I23, the are between the electrode I23 and the metallicnozzle Iti, the metallic nozzle MI, conductor IE3, terminal stud I I3 tothe terminal cable H5. The electrical circuit through the interrupter isextinguished by the extinction of the are drawn between the electrodeI23 and the metallic nozzle MI, this being caused by a blast of gasthrough the metallic nozzle MI. When the piston I21 is moved to the leftby the gas pressure stored within the insulating casing 91, 'it remainsin this position until a relatively low value of the pressure within thecasing 91, as a result of the pivotal action of the spring guide rodsI31.

It will thus be apparent that in Fig. 4 we have shown an interrupterwhich draws two arcs in. series, one of the arcs generating gas withinthe casing 91 to a pressure sufficient to enable the second are formedto be extinguished in a metallic nozzle MI. The design of the springsI35 is such that the piston I21 is not actuated to the left until thepressure within the casing 91 is sufficient to interrupt the are drawnbetween the electrode H3 and the metallic nozzle iii. It will beobserved that the are drawn between the arcing horns I51 and H5 willevolve gases from the gas evolving plates Ml, which gases being not willupon rising between the plates M1 become cooled and will generate afurther supply of gas at the upper ends of the plates Ml. Thus the gasfirst generated is cooled and augmented by the gas which is evolved fromthe upper ends of the plates Ml. The time which elapses between thefirst generation of gas from the plates i l? and the time the piston I21is moved by the pressure within the casing 91 to the left is sufficientfor the deionization of the gas initially formed by the are upon theplates Idl. Consequently, when the pressiu'e is sufii cient to actuatethe piston 112i to the left, and hence to draw a second are between theelectrode M3 and the nozzle MI, the gas which is ejected from the casinger is cooled and deionized suiticiently to effect a quickextinguishrnent of the are drawn between the electrode i253 and the Imetallic nozzle idi.

in the embodiment of our invention illustrated in Fig. 6, there is shownan insulating casing hi5, the ends of which are closed by the insuiatingclosure members it? and its. There is provided a movable contact iGiwhich engages a stationary contact 563 in the elosed=eircuit position oithe interrupter.

In the closed-circuit position oi the interrupter the electrical circuitthrough the interrupter consists of the terminal cable I65, terminalstud bolt it'i, flexible cable i659, movable contact Edi, stationarycontact its, magnetic blow-out coil iii, to terminal cable il'd. Alaminated iron core I15 is disposed within the blow-out coil i'iii, theends of the laminated iron core W5 being attached to magnetic polepieces Directly above the movable contact iiii is an arcing horn i 15.Above the stationary contact I63 is a second conducting arcing horn iei,Supported by insulating support members i 35 and disposed within theinsulating case I55 are a plurality of gas evolving insulating platesids, which may be formed of horn fiber, boric acid, or other materialwhich evolves a vapor or gas upon being subjected to an arc. Theconfigura= tion of the gas evolving plates I is more clearly shown inFig. 8. The gas evolving plates E85 are provided with a wedge-shapedslot till. When the plates I85 are assembled in stacked relation betweenthe insulating support members i l-5, the slots I81 form an arcingchamber generally illdicated by the reference numeral its.

Disposed in the upper end of the insulating casing I55 is a piston I91guided by bracket I25 which is biased by a compression spring I95 tocause a stem I 9I to close a vent I93 formed in a side of the casingI55. The piston I91 moves within the piston chamber I29 which is securedby a stud I3I to a wall of the casing I55, a vent I49 being providedtorelieve back-pressure on the left side of the piston I91. A stop I99 isprovided for the piston I91. The compression spring I95 thus biases thepiston I91 to the right, as viewed in Fig. 6, to close the vent I93 inthe insulating casing [55.

The operation of the interrupter will now be explained. When it isdesired to open the interrupter to break the current passingtherethrough, or when an overload exists in the external circuitconnected to the interrupter to result in an actuation of an externallyprovided trip mechanism, suitable contact operating mechanism, notshown, is actuated to move the movable contact I6! to the left away fromthe stationary contact I63. The arc thus drawn between the movablecontact I6I and the stationary contact I59 is moved by the blow-out coilIII upwards onto the arcing horns I19 and I8I. The arc, the position ofwhich is indicated by the reference numeral I83 in Fig. 6, moves upwardsto the upper ends of the arcing horns I19 and I8I into the arcingchamber I89. Within the arcing chamber I99 the arc reacts upon the gasevolving plates I85 to generate a gas. The gas so evolved raises thepressure within the insulating casing I55. There is provided sufficientspace between the plates I85 and the lower closure member I59 so thatthe gas generated within the plates I85 is accumulated in this storagespace, indicated generally by the reference numeral I85. When thepressure within the insulating casing I55 has raised suihciently to movethe piston I91 to the left against the biasing action of the compressionsprings I95, the stem I 9i moves away from the vent I95 to permit theejection from the insulating casing I55 of the accumulated gas stored inthe storage space I 85.

When the vent I95 opens. the accumulated gas stored in the storage spaceI86 rushes rapidly upward through the are drawn at the upper ends of thearcing horns I19 and I8I and out of the insulating casing I55 throughthe vent I93 to extinguish the arc drawn at the upper ends of the arcinghorns I19 and I8 I. The compression sprin I95 is so desi ned as toremain compressed until the gas pressure within the insulating casingI55 falls to a low value.

It will thus be seen that in the embodiment of our invention illustratedin Fig. 6, we have provided means for drawing an are between a movableand a stationary contact, blowing the arc upwards by means of a magneticblow-out coil I'II along a pair of arcing horns I19 and I8I into anarcing chamber I89, wherein gas is generated and stored below the arcingchamber I89 to a pressure sufiiciently high to blast upwards through theplates I85 to extinguish the are drawn therein when the piston I 91moves to the left to open the vent I93 in the wall of the casing I 55.Fig. '7, which is a fragmentary transverse cross-sectional view takensubstantially along the lines VIIVII in Fig. 6, and in the direction ofthe arrows, shows the disposition of the plates I85 within the casingI55. It will be apparent in Fig. 6, as was also true in Fig. 4 and Fig.1, that the gas initially generated in the gas evolving plates I95 iscooled by the upper ends of the plates I95 and in cooling evolves stillmore gas. It will furthermore be apparent that the time which isrequired before the pressure rises sufflciently within the casing I55 toactuate the piston I91 to the left is sufficient to'permit arecombination of the ions initially formed. The storage space I86 ispurposely provided below the plates I so that upon actuation of the psto I91 and the consequent opening of the vent I93, the gas will rushfrom the storage space I85 upwards through the arcing chamber I89 toextinguish the are which is positioned therein.

Fig. 9 is another embodiment of our invention, and it incorporates themovable contact operating mechanism of Fig. 1 with the utilization of apressure chamber similar to that of Fig. 6. The method of operation ofthe movable contact mechanism is identical to that already described inconnection with Fig. l. The method of arc extinction is also similar tothat alrecdy described in connection with Fig. 6.. However, as will beapparent, an external supply of arc extinguishing gas is furnished bythe storage tank I5. The check valve 35 in Fig. 1 has been omitted inFig. 9. A vent hole I99 is provided at the upper end of the pressurechamber I55.

Since the method of moving the movable contact IBI is identical to thatalready described in Fig. l, a further description seems unnecessary. Itsufiices to say that upon the movement of movable contact ISI to theleft to draw an arc between the movable contact IBI and the stationarycontact I53 this are is forced upwards between the two arcing horns I19,I8I by the combined action of the magnetic blow-out coil I1! and also bythe admission of arc extinguishing flui from the storage tank I5 upwardsthrough the vent 29L The magnetic blow-out coil I1I could be omitted,for the blast of arc extinguishing fluid upward from the conduit IIwould be sufiicient to raise the arc upwards between the arcing hornsI19 and I8! into the arcing chamber I89. As already described inconnection with Fig. 6, the arc reacts upon the gas evolving insulatingplates I85 to generate gas, which gas together with the gas comingupwards through the conduit I I is stored in the gas storage region I86positioned below the insulating plates I85. When the pressure within thecasing I55 is sufilcient to extinguish the arc in the stack of platesI85, the biasing action of the compression spring I will be overcome bythe pressure within the casing I55, and the piston I91 will move to theleft opening up vent hole I93. When this occurs the gas stored below theplates I85 will rush upwards through the plates I85 and will extinguishthe arc therein.

It will be observed that for the low and medium values of current theamount of gas generated from the plates I85 may be relatively small. Inthis event the pressure supplied by the storage tank I5 will besufficient to actuate the piston I91 and to extinguish the arc in thestack of plates I85, the gas in this case being stored in the storageregion I 8-5 until actutation of the piston I91 to the left. For thehigher values of current, on the other hand, the amount of gas generatedwithin the plates I85 will be relatively large and the gas will again bestored in the storage region IBG until actuation to the left of pistonI91, at which time the vent I 93 will be opened and the gas will rushupwards through the plates I85 to extinguish the arc therein. The ventI99 remains open at all times. The vent I99 may be omitted but ifprovided it serves to regulat the pressure within the chamber I55.

Where the advantages of a dry-type device are not required an arcextinguishing liquid can be used in any of the breakers described thusfar. Instead of the arc reacting on a gas evolving solid, the arc couldreact upon a liquid disposed in the pressure .chambers in the variousbreakers to raise the pressure therein and to actuate the respectivepistons. By our describing our invention as applied to compressed gascircuit interrupters, we do not mean to limit the scop of our inven tionto gas type breakers, except where specifically claimed, but intend bythe following claims to indicate the scope of our invention.

When the term arc extinguishing fluid is used in the specification andin the claims, such term is meant to includea liquid as well as agaseous arc extinguishing fluid.

Although we have shown and described certain specific embodiments of ourinvention, we are fully aware that many modifications thereof arepossible. Our invention, therefore, is not to be restricted exceptinsofar as is necessitated by the prior art and the spirit of theappended claims.

We claim as our invention:

1. In a circuit interrupter, means defining a substantially closedchamber, means for establishing an are within said chamber, a pluralityof slotted plates disposed within said chamber capable of evolving a gasupon being engaged by an are, means for causing said are to move intothe slots of said plates thereby engaging the plates to assist raisingthe pressure within said chamber, venting means for relieving thepressure within said chamber, and opening means for said venting meansresponsive to the pressure within said chamber.

2. In a circuit interrupter, a substantially closed pressure chamber,arc extinguishing fluid disposed within said pressure chamber, means forestablishing an are within said pressure chamber, a plurality of spacedslotted plates disposed within said chamber capable of evolving a vaporupon contacting an arc, means for causing said are to move into theslots of said plates thereby contacting the plates to assist raising thepressure within said pressure chamber, and venting means for relievingthe pressure within said chamber.

3. In a circuit interrupter, means defining a substantially closedchamber, a plurality of plates disposed within said chamber capable ofevolving a gas upon being engaged by an are, means for establishing atleast two serially related arcs within said chamber, at least one ofsaid established arcs being established first, means for causing saidfirst established arc to engage said plates to form gas and hence toassist raising the pressure within said chamber, and means for assistingthe extinguishment of at least one of said later, established arcs bythe increased pressure within said chamber.

4. In a circuit interrupter, a substantially closed chamber, arcextinguishing fluid disposed within said chamber, a plurality of spacedslotted plates disposed within said chamber capable of evolving a vaporupon contacting an arc, means for establishing a plurality of seriallyrelated arcs within said chamber, one of said arcs being estab lishedprior to the formation of another of said arcs, means for causing atleast one of said first established arcs to engage said slotted platesto assist raising the pressure within said chamber, and means forutilizing the raised pressure within said chamber to assist in theextinguishment of one of said later established arcs.

5. In a circuit interrupter, a substantially closed pressure chamber,venting means for said pressure chamber operable upon a predeterminedpressure within said pressure chamber, means for establishing one ormore arcs within said chamber, a plurality of spaced plates disposedwithin said pressure chamber capable of evolving a gas upon beingcontacted by an arc, means for causing one of said arcs to engage saidplates to assist raising the pressure within said pressure chamber, andmeans for utilizing at least a part or the evolved gas to assist in theextinguishment of one of said arcs.

6. In a circuit interrupter, a substantially closed chamber, means forestablishing one or more arcs within said chamber, a plurality ofslotted plates disposed within said chamber capable of, evolving a gasupon being contacted by an arc, means for causing at least one of saidarcs to move into the slots of said plates to assist rais ing thepressure within said chamber, and means for utilizing at least a part ofthe gas so evolved by the action of said one or more arcs reacting onsaid plates to assist in the extinguishment of the electrical circuitpassing through said inter= rupter, said last-mentioned means comprisingpressure relieving means responsive to the pressure within said chamber.

7. In a circuit interrupter, means defining a substantially closedpressure chamber, means for establishing a plurality of arcs within saidchamber, a material disposed within said chamber capable of evolving agas upon being contacted by an arc, means for causing at least one or"said arcs to engage said material to assist raising the pressure withinsaid pressure chamber, and means for feeding arc extinguishing gas underpressure from an external source into said pressure chamber dependentupon the pressure therein to assist in extinguishing another of saidarcs.

8. In a circuit interrupter, means defining a substantially closedpressure chamber, an are ex .tinguishing fluid disposed within saidchamber,

a plurality of slotted gas evolving plates, means for establishing oneor more arcs within said chamber to assist raising the pressure withinsaid P chamber by moving into the slots of said plates,

and means for feeding arc extinguishing fluid under pressure from anexternal source into said chamber dependent upon the pressure therein.

9. In a circuit interrupter, means defining a substantially closedpressure chamber, venting means for said pressure chamber responsive tothe pressure therein, an arc extinguishing fluid disposed within saidchamber, means for establishing one or more arcs within said chamber toassist raising the pressure within said chamber, an external. source ofarc extinguishing fluid under pressure, and means for feeding areextinguishing fluid under pressure from said external source into saidchamber upon a circuit opening operation of said interrupter.

10. In a circuit interrupter, means defining a substantially closedpressure chamber, are extinguishing fluid disposed within said pressurechamber, means for establishing one or more arcs within said pressurechamber, means for causing at least one of said arcs to raise thepressure within said chamber, venting means for relieving the pressurewithin said chamber, opening means for aid venting means responsive tothe pressure within said chamber, and means responsive to the pressurewithin said chamber for permitting the feeding of arc extinguishingfluid under pressure from an external source into said chamber. 7

11. In a circuit interrupter, means defining a substantially closedpressure chamber, are extinguishing fluid disposed within said pressurechamber, means for establishing two or more serially related arcs withinsaid pressure chamher, an external source of arc extinguishing fluidunder pressure, means for utilizing at least one of said arcs to assistraising the pressure within said chamber, means for introducing intosaid chamber arc extinguishing fluid under pressure from said externalsource, and means for utilizing both the pressure from said externalsource and also the "pressure generated by said one are within saidchamber to assist in the extinguishment of the electrical circuitpassing through said interrupter.

12. In a circuit interrupter, means defining a substantially closedpressure chamber, are extinguishing fluid disposed within said pressurechamber, an external source of arc extinguishing fluid under pressure,means for establishing one or more arcs within said pressure chamber,means. for utilizing at least one of said established arcs to assist inraising the pressure within said pressure chamber, means for introducingarc extinguishing fluid under pressure from said external source intosaid pressure chamber, means for causing the pressure of the introducedarc extinguishing fluid to primarily extinguish the electrical circuitthrough said interrupter during relatively low values of current, meansfor causing the raised pressure created by said one or more arcs toprimarily extinguish the electrical circuit through said interrupterduring relatively high values of current, and venting means for saidchamber responsive to the pressure therein.

13. In a circuit interrupter, means defining a substantially closedpressure chamber, arc extin guishing fluid disposed within said pressurechamber, an external source of arc extinguishing fluid under pressure,means for establishing one or more serially related arcs within saidpressure chamber, means for causing at least one of said seriallyrelated arcs to raise the pressure within said chamber, meansresponsiveto the pressure within said chamber for permitting theintroduction of arc extinguishing fluid under pressure from saidexternal source into said chamber, and venting means for said pressurechamber responsive to the pressure therein.

14. In a circuit interrupter, means defining a substantially closedpressure chamber, arc extinguishing fluid disposed within said pressurechamber, an external source of arc extinguishing fluid under pressure,means for establishing one or more arcs within said pressure chamber,means for causing at least one of said arcs to raise the pressure withinsaid pressure chamber, means responsive to the operation of saidinterrupter to introduce arc extinguishing fluid under pressure fromsaid external source into said chamber, means for causing the pressureof the introduced arc extinguishing fluid to primarily extinguish theelectrical circuit through said interrupter during relatively low valuesof current, means for causing the raised pressure created by said one ormore arcs to primarily extinguish the electrical circuit through saidinterrupter during relatively high values of current, and venting meansfor said pressure chamber responsive to gas upon being subjected to anarc, means for causing at least one of said arcs to contact said platesto raise the pressure within said chamber, and venting mean adjacent atleast one of said serially related arcs for relieving the pressurewithin said chamber.

16. In a circuit interrupter, means defining a substantially closedchamber, means for establishing two or more serially related arcs withinsaid chamber, a plurality of spaced slotted plates disposed within saidchamber capable of evolving a gas upon being contacted by an electricarc, means'for causing at least one of said serially related arcs tomove into the slots in said plates to raise the pressure within saidchamber, venting means disposed adjacent to at least one of saidserially related arcs, and means for venting at least a part of the gasstored within said chamber through said venting means to assist in theextinguishment of said one or more arcs disposed adjacent thereto.

1'7. In a circuit interrupter, means defining a substantially closedchamber, means for establishing two or more serially related arcs withinsaid chamber, a plurality of plates disposed within said chamber capableof evolving a gas upon being contacted by an electric arc, means forcausing at least one of said serially related arcs to contact saidplates to raise the pressure within said chamber, venting meansresponsive to the pressure within said chamber disposed adjacent to atleast one of said arcs, said venting means being operative to cause ablast of gas out of said chamber to result in the extinguishment of thearc disposed adjacent thereto.

18. In a circuit interrupter, means defining a substantially closedpressure chamber, are extinguishing fluid disposed within said pressurechamber, an external source of arc extinguishing fluid under pressure,means for establishing two or more serially related arcs within saidpressure chamber, venting means for said pressure chamber responsive tothe pressure therein, said venting means disposed adjacent to at leastone of said arcs, means for causing at least one of said arcs to raisethe pressure within said pressure chamber, means responsive to theoperation of said interrupter to introduce arc extinguishing fluid underpressure from said external source into said chamber, said arcextinguishing fluid under pressure from said external source dischargingfrom said pressure chamber through said venting means to primarilyextinguish said one or more serially related arcs disposed adjacent tosaid venting means during relatively low values of current, theincreased pressure created by said one or more serially related arcsserving primarily on relatively high values of current to extinguishsaid one or more serially related arcs disposed adjacent to said ventingmeans.

19. In a compressed gas circuit interrupter, a closed chamber, means forestablishing twoserially related arcs within said chamber, venting meansfor said chamber responsive to the pressure therein, a material disposedwithin said chamber capable of evolving a gas upon contacting an arc,said material being provided in the form of a plurality of spacedplates, one of said arcs being drawn adjacent to said plates, the otherof said arcs being formed adjacent to said venting means upon theoperation thereof, an external supply of arc extinguishing gas underpressure, means responsive to the operation of said interrupter forintroducing gas from said external source into said chamber, saidintroduced gas blowing the are formed adjacent to said plates intointimate engagement with said plates to increase the pressure withinsaid chamber, means for cutting on the external supply of gas it thegenerated gas is sufficient to interrupt said are drawn upon theoperation of said venting means, the rising pressure within said chamberactuating said venting means at a predetermined pressure, the dischargeof the gas through said venting means causing an interruption of the ardrawn adjacent thereto.

20. In a circuit interrupter, a closed chamber, venting means for saidchamber responsive to the pressure therein, a plurality of spacedinsulating plates formed of a material which evolves a gas whencontacting an arc, means for establishing two serially related arcswithin said chamber, one of said arcs being moved adjacent to saidplates, means for causing said are to intimately engage said plates toraisethe pressure within said chamber, the other of said seriallyrelated arcs being drawn adjacent to said venting means upon theoperation thereof, the operation of said interrupter being such that theincreased pressure resulting from the generation of gas from said platesis suificient to actuate said venting means to draw said are adjacentthereto and to extinguish the same by a discharge of the gas from saidchamber out through said venting means.

21. In a circuit interrupter, means defining a substantially closedchamber, means for establishing an are within said chamber, a pluralityof insulating plates formed of a material which evolves a gas uponcontactingan arc, means for causing said are to engage said plates togenerate gas to raise the pressure within said chamber, venting meansfor said chamber actuated upon a predetermined pressure therein, a gasstorage space within said chamber so positioned that the stored gas musttraverse said plates before discharging from said chamber through saidventing means, the discharge of said stored gas upon the actuation ofsaid venting means causing an extinction of said are when it ispositioned adjacent said plates.

22. In a circuit interrupter of the gas-blast type, a substantiallyclosed chamber, means for establishing an arc within thechambenaplurality of insulating plates composed of gas-evolvingmaterial, an external source of compressed 8 s. and means for feedingcompressed gas from the external source into the chamber to force theare against the plates to cause thereby emission of evolved gas.

23. In a circuit interrupter or the gas-blast type, a substantiallyclosed chamber, means for establishing an are within the chamber, aplurality or insulating plates composed or gas-evolving material, anexternal source of compressed gas, and means responsive to the pressurewithin the chamber for feeding compressed gas from the external sourceinto the chamber to force the are against the plates to cause therebyemission of evolved gas.

24. In a circuit interrupter or the gas-blast t p a substantially closedchamber, means for establishing an are within the chamber, a pluralityof insulating plates composed t gas-evolving material, an externalsource or compressed gas, means for feeding compressed gas from theexternal source into the chamber to force the are against the plates tocause thereby emission of evolved gas, and venting means for the chamberopened upon the attainment of a predetermined pressure therein.

25. In a circuit interrupter of the gas-blast type, a substantiallyclosed chamber, means for establishing an arc within the chamber, aplurality of insulating plates composed of gas-evolving material, anexternal source of compressed gas, means responsive to the pressurewithin the chamber for feeding compressed gas from the external sourceinto the chamber to force the are against the plates to cause therebyemission of evolved gas, and venting means for the chamber opened uponthe attainment of a predetermined pressure therein.

26. In a circuit interrupter of the gas-blast type, a substantiallyclosed chamber, means for establishing an are within the chamber, aplurality of insulating plates composed of gas-evolving material, anexternal source of compressed gas, means for feeding compressed gas fromthe external source into th chamber to force the are against the platesto cause thereby emission of evolved gas, venting means for the ch mberopened upon the attainment of a predetermined pressure therein, andmeans for drawing a second serially related arc adjacent the ventingmeans.

27. In a circuit interrupter of the gas-blast type, a substantiallyclosed chamber, means for establishing an are within the chamber, aplurality of insulating plates composed of gas-evolving material, anexternal source of compressed gas, means responsive to th pressurewithin the chamber for feeding compressed gas from the external sourceinto the chamber to force the are against the plates to cause therebyemission of evolved gas, venting means for the chamber opened upon theattainment of a predetermined pressure therein, and means for drawing asecond serially related are adjacent the venting means.

28. In a circuit interrupter of the gas-blast type, a substantiallyclosed chamber, means for establishing an are within the chamber, aplurality of insulating plates-composed of gas-evolving material, anexternal source of compressed gas, means for feeding compressed gas fromthe external source into the chamber to force the are against th platesto cause thereby emission of evolved gas, venting means for the chamberopened upon the attainment of a predetermined pressure therein, meansfor drawing a second serially related are adjacent the venting means,and the latter arc being extinguished by a blast of gas through theventing means.

29. In a circuit interrupter of the gas-blast type, a, substantiallyclosed chamber, means for establishing an are within the chamber, aplurality of insulating plates composed of gas-evolving material, anexternal source of compressed gas, means responsive to the pressurewithin the chamber for feeding compressed gas from the external sourceinto the chamber to force the are against the plates to cause therebyemission of evolved gas, venting means for the chamber opened upon theattainment of a predetermined pressur therein, means for drawing asecond serially related are adjacent the venting means, and the latterarc being extinguished by a blast of gas through the venting means.

BENJAMIN P. BAKER. HERBERT L. RAWLINB.

